共查询到20条相似文献,搜索用时 31 毫秒
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ψ'→J/ψ π^+π^-提供了一个抽取低于0.59GeV的ππ S波相移的新途径,基于在树图衰变振幅中忽略D波的近似,给出了从ψ'→J/ψ π^+π^-的ππ不变质量谱中得到ππ S波相移的公式。 相似文献
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《中国科学:物理学 力学 天文学(英文版)》2015,(7)
The semileptonic decays B+c →P(V) +L++νL and the nonleptonic decays B+c →P(V) + L, where P(V) denotes a pseudoscalar(vector) charmonium or(ˉbs)-meson, and L denotes a light meson, are studied in the framework of improved instantaneous BetheSalpeter(BS) equation and the Mandelstam formula. The numerical results(width and branching ratio of the decays) are presented in tables, and in order to compare conveniently, those obtained by other approaches are also put in the relevant tables. Based on the fact that the ratio BR(B+c →ψ(2S)π+)/BR(B+c →J/ψπ+)= 0.24+0.023-0.040 estimated here is in good agreement with the observation by LHCb BR(B+c →ψ(2S)π+)BR(B+c →J/ψπ+)=0.250±0.068(stat)±0.014(syst)±0.006(B), one may conclude that with respect to the decays the present framework works quite well. 相似文献
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SHEN Xiao-Yan 《中国物理C(英文版)》2008,32(6):448-451
We reported the observation of Y(2175) in φf0(980) mass spectrum in J/ψ→ηφf0(980) with f0(980)→π+π- and the observation of a broad 1-- resonance of K+K-mass in J/ψ→K+K-π0. The results from the partial wave analyses of Jψ→γπ+π- and γπ0π0, as well as J/ψ→pK-∧. are also presented. 相似文献
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Based on real data,a new parameterized model of the main drift chamber response is proposed.In this model,we tune the ratio of good hits and the residual distribution separately.By data quality checking,the diference between simulation and data in track reconstruction efciency reduces from 1%to 0.5%averagely for the pion in J/ψ→π+ππ0,and the momentum resolution agreement improves significantly for the proton in J/ψ→ppˉ. 相似文献
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观测到ψ(3770)衰变到J/ψπ+π—非DD末态迹象.利用工作在北京正负电子对撞机上的北京谱仪探测器在质心系能量3.773GeV附近获取的8.0±0.5pb-1数据样本,共观测到6.8±3.0个ψ(3770)→J/ψπ+π—事例.由此得到的分支比为BF(ψ(3770)→J/ψπ+π—)=(0.59±0.26±0.16)%,其对应的分宽度为Γ(ψ(3770)→J/ψπ+π—)=(139±61±41)keV. 相似文献
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PING Rong-Gang 《中国物理C(英文版)》2010,34(6):626-631
Using ~14×106ψ(2S) and ~58×106J/ψ data collected at BESⅡ/BEPC,the branching fraction of ψ(2S) →Ω+Ωˉ+ is measured with about 5σ statistical significance.The Λ electric dipole and Λ decay parameter are studied using the decay J/ψ→ΛΛ→ ppˉπ+π-.Using(106±3)×106 ψ(2S) decays collected at BESⅢ/BEPCⅡ,we have obtained some interesting physics results.The branching fractions of χcJ →π0π0,ηη are measured with precision improved.The mass and width of hc(11P1) state,together with the branching fractions of Br(ψ(2S) →π0hc) and Br(hc →γηc) are the first measurements.Surprisingly,the decays of χc1 →φφ,ωω,and ωφ are firstly observed in BESⅢ data. 相似文献
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The π+π- transition of heavy quarkonia in decay ψ(2S) ψ(2S)→π+π-J/ψ is studied. With the BESII data on the decay ψ(2S)→π+π-J/ψ, we update the values of coupling constants (gi) and chromopolarizability (аψ(2S)J/ψ) in this process. 相似文献
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We search for the ψ(4S) state in the B~±→ηJ/ψK~± and e~+e~-→ηJ/ψ processes based on the Belle measurements with the assumed mass M =(4230±8) MeV/c~2 and width Γ =(38±12) MeV. No significant signal is observed in the ηJ/ψ mass spectra. The 90% confidence level upper limit on the product branching fraction B(B~±→ψ(4S)K~±)B(ψ(4S)→ηJ/ψ) 6.8×10~(-6) is obtained in the B~±→ηJ/ψK~± decays. By assuming the partial width of ψ(4S)→e~+e~-to be 0.63 ke V, a branching fraction limitB(ψ(4S)→ηJ/ψ) 1.3% is obtained at the 90%confidence level in e~+e~-→ηJ/ψ, which is consistent with the theoretical prediction. 相似文献
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The study of ρ-ω mixing has mainly focused on vector meson decays with isospin I = 1, namely theρ(ω)→π+π- process. In this paper, we present a study of ρ-ω mixing in ρ(ω)→π+π-π0(I = 0) using a flavor parameterization model for the J/ψ→VP process. By fitting a theoretical framework to PDG data, we obtain the SU(3)-breaking effect parameters sV = 0.03±0.12, sP = 0.17±0.17 and the ρ-ω mixing polarization operatorΠρω =(0.006±0.011) GeV2. New values are found for the branching ratios when the mixing effect is incorporated:Br(J/ψ→ωπ0)=(3.64±0.37)×10-4, Br(J/ψ→ωη)=(1.48±0.17)×10-3, Br(J/ψ→ωη)=(1.55±0.56)×10-4, these are different from the corresponding PDG2012 values by 19%, 15% and 15%, respectively. 相似文献
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The π^+π^ transition of heavy quarkonia in decay ψ(2S) →π^+π^-J/ψ is studied. With the BESII data on the decay ψ(2S) →π^+π^-J/ψ, we update the values of coupling constants (gi) and chromopolarizability (αψ(2s)J/ψ) in this process. 相似文献
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本文引进过程e~+e~-→J/ψ→γB,B→P_1P_2P_3的矩的光子角分布来讨论■E疑难,得到了判断J/ψ→γKK_π过程中产生的共振峰是否包含E(1~(++))分量的一个有效判据. 相似文献
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利用北京谱仪(BES)上取得的ψ(2S)数据,对ψ(2S)→π+π-J/ψ,J/ψ→1+1-和J/ψ→任意末态两个过程进行了细致的研究,得到J/ψ的轻子道衰变分支比为B(J/ψ→e+e-)=(5.90±0.07±0.16)%和B(J/ψ→μ+μ-)=(5.96±0.08±0.16)%,由此给出Be/Bμ的值为0.990±0.018±0.024.假定Be=Bμ,J/ψ的轻子道衰变分支比为B(J/ψ→1+1-)=(5.93±0.05±0.16)%.上述结果可用来估计强相互作用耦合常数αs和QCD减除参数∧. 相似文献
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为了便于BES(北京谱仪)做数据分析,本文给出了在J/ψ→ωX,ω→2π或3π,X→KKπ反应中寻找1+-奇特态的一些新的关系式.并且对于在三级二体衰变过程J/ψ→ωX,ω→2π或3π,X→K*K,K*→Kπ中如何寻找1+-奇特态的问题作了讨论. 相似文献
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用BESⅠ的 7.8× 1 0 6 J/ ψ数据更为精确地测定了J/ ψ→π0 3 (π+π- )和J/ ψ→ω2 (π+π- )的分支比 (Br(J/ ψ→π0 3 (π+π- ) ) =( 2 .52± 0 .0 6± 0 .4 3 ) % ,Br(J/ ψ→ω2 (π+π- ) ) =( 1 .3 1± 0 .0 9± 0 .2 1 ) % .同时对 4π不变质量谱和ωππ不变质量谱进行研究分析 ,试图观察是否存在有兴趣的信号 . 相似文献
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基于BESⅠ的7.8×106的J/ψ数据样本,研究了J/ψ→ωπ+π-衰变.
在反冲ω粒子的π+π-的不变质量谱中清楚地观察到了一个低质量端的突起,此突起既不来自相空间效应,又不来自本底.
根据分波分析,此低质量端的突起是一个0+ +的共振态,即σ粒子.
如果用常数宽度的Breit-Wigner函数来拟合σ粒子,其质量和宽度分别为384±66MeV和458±100MeV,与其对应的极点位置是(434±78)-i(202±43)MeV. 相似文献